PALEONTOLOGIC RESOURCE INVENTORY/
IMPACT ASSESSMENT TECHNICAL REPORT
prepared in support of
CITY OF VERNON’S PROPOSED
MALBURG GENERATING STATION PROJECT
VERNON, LOS ANGELES COUNTY, CALIFORNIA
Submitted to:
ENSR International
1220 Avenida Acaso
Camarillo, California 93012-8738
Submitted by:
E. Bruce Lander, Ph.D.
Paleo Environmental Associates, Inc.
2248 Winrock Avenue
Altadena, California 91001-3205
626/797-9895
2001-16
July 2001vernon-afc.doc
PALEO ENVIRONMENTAL ASSOCIATES
TABLE OF CONTENTS
Section 1Introduction...... 1
1.1Background...... 1
1.2Personnel...... 1
Section 2Environmental Setting...... 2
2.1Methods...... 2
2.1.1Stratigraphic Inventory...... 2
2.1.2Paleontologic Resource Inventory...... 2
2.1.3Paleontologic Resource Assessment Criteria...... 2
2.2Results...... 4
2.2.1Stratigraphic Inventory...... 4
2.2.2Paleontologic Resource Inventory and Assessment by Rock Unit...... 4
2.2.2.1Alluvium...... 4
2.2.2.2Artificial Fill...... 6
2.2.3Summary...... 6
Section 3Environmental Impacts...... 8
3.1Construction Phase Impacts...... 8
3.1.1Significance Criteria...... 8
3.1.2Impact Assessment...... 8
3.1.2.1Alluvium...... 8
3.1.2.2Artificial Fill...... 9
3.2Operational Phase Impacts...... 9
3.3Abandonment/Closure...... 9
3.4Cumulative Impacts...... 9
Section 4Mitigation Measures...... 10
4.1Construction Phase...... 10
4.1.1Mitigation Program Design Criteria...... 10
4.1.2Beneficial Environmental Effects of Mitigation Program...... 10
4.1.3Qualifications of Paleontologist Conducting Mitigation Program...... 11
4.1.4Compliance with CEC and Professional Society Guidelines...... 11
4.1.5Mitigation Measures...... 11
4.1.5.1Task1—Retention of Paleontologist...... 11
4.1.5.2Task2—Museum Storage Agreement...... 11
4.1.5.3Task3—Preconstruction Coordination...... 11
4.1.5.4Task4—Paleontologic Monitoring and Fossil/Sample Recovery 11
4.1.5.5Task5—Final Laboratory Tasks...... 12
4.1.5.6Task6—Reporting...... 12
4.2Operational Phase...... 12
4.3Abandonment/Closure...... 12
4.4LORS Compliance...... 12
4.4.1Federal Authorities and Administering Agencies...... 12
4.4.2State Authorities and Administering Agencies...... 12
4.4.3Local Authorities and Administering Agencies...... 14
Section 5Acronyms...... 15
Section 6Literature Cited...... 16
Table 1Applicable State LORS Regarding Paleontologic Resources...... 13
Figure 1Proposed Malburg Generating Station Project Paleontologic Resource Sensitivity Map...... 5
1
PALEO ENVIRONMENTAL ASSOCIATES
SECTION 1
INTRODUCTION
1.1BACKGROUND
Paleontologic resources include fossil remains, fossil sites, associated specimen data and corresponding geologic and geographic site data, and the fossil-bearing strata. This technical report summarizes the results of the paleontologic resource inventory/impact assessment conducted by Paleo Environmental Associates, Inc. (PEAI), in support of the City of Vernon’s proposed Malburg Generating Station Project Application for Certification (AFC). The California Energy Commission (CEC) has required this inventory/impact assessment because of the potential for fossil sites and remains being encountered by earth-moving activities associated with construction of the Project.
1.2PERSONNEL
This technical report was prepared by Dr. E. Bruce Lander, a paleontologist with PEAI, Altadena, California. Dr. Lander has a Ph.D. degree in paleontology and has conducted research, authored published scientific contributions, and prepared environmental impact review documents on the paleontologic resources of California in support of other major construction projects, including a number of CEC-permitted energy-related projects. Dr. Lander conducted the literature review and field survey for this report.
SECTION 2
Environmental Setting
The Project site lies on the coastal floodplain of the Los Angeles River, which lies 0.6 mile north-northeast of the Project site in the central Los Angeles basin. The central Los Angeles basin in the Project site vicinity is underlain by strata consisting of unconsolidated alluvial fan and floodplain deposits derived from the hills and mountains ranges bordering the northern margin of the central Los Angeles basin and subsequently deposited by the Los Angeles River (see Dibblee, 1989; Jennings, 1962; Yerkes and others, 1965).
The Project site is underlain by artificial fill, which consists of the strata that once lay within a few feet of the surface of the Project site subsequently were disturbed as a result of previous earth-moving activities, particularly grading and other earth-moving activities associated with the construction and subsequent removal of storage tanks and the excavation of a retention basin.
Paleontologic resources of the Project site include a sedimentary or stratigraphic rock unit that has a potential for yielding fossil remains because it has yielded fossil remains at previously recorded fossil sites near the Project site. Fossils, the remains or indications of once-living organisms, are a very important scientific resource because of their use in 1) documenting the evolution of particular groups of organisms, 2) reconstructing the environments in which they lived, 3) and in determining the ages of the strata in which they occur and of the geologic events that resulted in the deposition of the sediments comprising these strata.
2.1Methods
The following tasks were conducted to develop a baseline paleontologic resource inventory of the Project site by rock unit, and to assess the potential paleontologic productivity and the paleontologic/scientific importance of each rock unit, these assessments being based on the fossil remains previously recorded from the rock unit in the Project site vicinity. These tasks were completed in compliance with CEC (1997) and Society of Vertebrate Paleontology (SVP, 1995) guidelines for assessing the importance of the paleontologic resources in an area of potential environmental effect.
2.1.1Stratigraphic Inventory
Geologic maps and reports covering the surficial geology of the Project site were reviewed to determine the rock units exposed at the Project site, particularly those rock units known to be fossiliferous, and to delineate their respective areal distributions.
2.1.2Paleontologic Resource Inventory
Published and unpublished geologic and paleontologic literature was reviewed to document the number and locations of previously recorded fossil sites at and near the Project site from each rock unit exposed at the Project site, and the types of fossil remains the rock unit has produced locally. The literature review was supplemented by archival searches conducted at the Natural History Museum of Los Angeles County Vertebrate Paleontology Section (LACMVP) and the San Bernardino County Museum (SBCM), Redlands, California, for additional information regarding the occurrences of fossil sites and remains at and near the Project site. A field survey of the Project site was conducted on June 29, 2001 to document the condition of any previously recorded fossil site, the presence of any previously unrecorded fossil site, and/or of strata suitable for containing fossil remains.
2.1.3Paleontologic Resource Assessment Criteria
The paleontologic importance (high, moderate, low, none, undetermined) of a rock unit exposed at the Project site is the measure most amenable to assessing the scientific importance of the paleontologic resources of the Project site because the areal distribution of a rock unit can be delineated on a topographic map. The paleontologic importance of a rock unit reflects 1) its potential paleontologic productivity and 2) the scientific importance of the fossils it has produced locally.
The potential paleontologic productivity (high, moderate, low, none, undetermined) of a rock unit exposed at the Project site is based on the abundance/densities of fossil specimens and/or previously recorded fossil sites in exposures of the unit at and near the Project site. Exposures of a specific rock unit at the Project site are most likely to yield fossil remains representing particular species in quantities or densities similar to those previously recorded from the unit at and near the Project site. The criteria for establishing the potential paleontologic productivity of a rock unit exposed at the Project site are described below.
1)High potential: rock unit contains comparatively high density of previously recorded fossil sites and has produced numerous fossil remains at and/or near Project site, and is very likely to yield additional similar remains at Project site.
2)Moderate potential: rock unit contains relatively moderate density of previously recorded fossil sites and has produced some fossil remains at and/or near Project site, and is somewhat likely to yield additional similar remains at Project site.
3)Low potential: rock unit contains no or comparatively low density of previously recorded fossil sites and has yielded very few or no fossil remains near Project site, and is not likely to yield any remains at Project site.
4)Undetermined potential: rock unit has limited or no exposure at Project site, is poorly studied, contains no previously recorded fossil site, and has produced no fossil remains near Project site. However, in Project site region, same or correlative and/or lithologically similar rock unit contains sufficient recorded fossil sites to suggest rock unit at Project site has at least a moderate potential for containing unrecorded fossil sites (note: elsewhere in California, exposures of rock units with few or no prior recorded fossil sites have recently proven abundantly fossiliferous during surveying, monitoring, or processing of fossiliferous rock samples as part of mitigation programs for other construction projects).
5)No potential: unfossiliferous igneous and high-grade metamorphic rock units with no potential for containing any unrecorded fossil site or yielding any fossil remains.
A fossil specimen is considered scientifically highly important if it is 1) identifiable, 2) complete, 3) well preserved, 4) age diagnostic, 5) useful in environmental reconstruction, 6) a type or topotypic specimen, 7) a member of a rare species, 8) a species that is part of a diverse assemblage, and/or 9) skeletal element different from, or a specimen more complete than those now available for its species. Identifiable fossil land mammal remains, for example, are considered scientifically highly important because of their potential use in providing very accurate age determinations and environmental reconstructions for the rock units in which they occur. The geologic age of fossil land plant remains can be determined by carbon-14 dating analysis. Moreover, such remains are comparatively rare in the fossil record.
Using the definitions presented above, the paleontologic importance of a rock unit exposed at the Project site would be assessed using the following criteria.
1)High importance: rock unit has comparatively high potential for containing unrecorded fossil sites and for yielding scientifically important fossil remains at Project site similar to those previously recorded from rock unit at and/or near Project site.
2)Moderate importance: rock unit has relatively moderate potential for containing unrecorded fossil sites and for yielding scientifically important fossil remains at Project site similar to those previously recorded from rock unit near Project site.
3)Low importance: rock unit has comparatively low potential for containing any unrecorded fossil site or for yielding any scientifically important fossil remains at Project site.
4)Undetermined importance: rock unit for which too few data are available from Project site and vicinity to allow an accurate assessment of its potential for containing any unrecorded fossil site or for yielding any scientifically important fossil remains at Project site.
5)No importance: unfossiliferous igneous and high-grade metamorphic rock units having no potential for containing any unrecorded fossil site or for yielding any fossil remains.
Note, however, that any fossil site containing identifiable fossil remains and the fossil-bearing layer are considered highly important paleontologically, regardless of the paleontologic importance of the rock unit in which the site and layer occur.
The following tasks were completed to establish the paleontologic importance of each rock unit exposed at the Project site.
1)The scientific importance of fossil remains recorded from a rock unit exposed at the Project site was assessed.
2)The potential paleontologic productivity of the rock unit was assessed, based on the density of fossil remains and/or previously recorded and newly documented fossil sites it contains at and/or near the Project site.
3)The paleontologic importance of the rock unit was assessed, based on its documented and/or potential fossil content at the Project site.
This method of resource assessment is the most appropriate for an areal paleontologic resource investigation of the Project site because discrete levels of paleontologic importance can be delineated on a topographic/geologic map.
2.2RESULTS
2.2.1Stratigraphic Inventory
The Project site lies on the northwest-trending central block of the Los Angeles basin, which, in turn, is situated near the northwestern corner of the Peninsular Ranges Province, where major linear geologic structures (faults, folds) and geographic features (mountains, valleys) trend in a northwesterly direction (see Jahns, 1954; Yerkes and others, 1965). The central block of the Los Angeles basin is bounded by the Newport-Inglewood Fault to the southwest, the Santa Monica Fault to the northwest, and by the Whittier Fault to the northeast (see Yerkes and others, 1965).
Regional surficial geologic mapping of the Project site and vicinity is provided by Jennings (1962) at a scale of 1:250,000. Mapping Jennings (1962) indicates that the entire Project site is underlain by Holocene alluvium, which locally consists of unconsolidated Los Angeles River floodplain and alluvial fan deposits of silt, sand, and gravel derived from the hills and mountain ranges that form the northern border of the central Los Angeles basin (see Dibblee, 1989; Yerkes and others, 1965). A surficial geologic map of the Project site is presented as Figure 1.
During the field survey conducted in support of the AFC, the surface of the Project site was found to be highly disturbed by previous earth-moving activities and to be underlain mostly if not entirely by unmapped artificial fill, which presumably includes disturbed strata at the top of the stratigraphically underlying alluvium.
2.2.2Paleontologic Resource Inventory and Assessment by Rock Unit
2.2.2.1Alluvium.—An inventory of the paleontologic resources of the alluvium is presented below and the paleontologic importance of these resources is assessed. Although neither the literature review, the archival searches, nor the field survey conducted for this inventory documented any previously recorded fossil site as occurring at the Project site, a number of previously recorded fossil sites were documented as occurring in the alluvium near the Project site, some in the downtown Los Angeles area. The fossil remains from most of these fossil sites were recovered as part of paleontologic resource impact mitigation programs conducted in support of other major construction projects.
Figure
The fossilized wood, pollen, and spores of land plants determined to be 5,020 + 80 years (middle Holocene) in age were recovered at a stratigraphic level 5 feet above the base of the younger alluvium and at a depth approximately 20 feet below grade at University of California Museum of Paleontology (UCMP) fossil site PB 98033 in the ancestral Los Angeles River channel at Union Station (Lander, 1997). Additional fossilized wood fragments occurred at shallower depths (Lander, 1997).
The fossilized shells of nonmarine mollusks (fresh-water snails and clams, land snails), the fossilized valves of fresh-water ostracods (bivalved crustaceans), the fossilized bones and teeth of continental vertebrates (fresh-water fishes, frogs, lizards, snakes, birds, shrews, rabbits, rodents), the fossilized logs of cottonwoods, and the fossilized pollen and spores of numerous other land plant species were recovered from a stratigraphic interval in the lower 5 to 10 feet of the younger alluvium and at depths approximately 44 to 60 feet below grade at the Metro Red Line Universal City station (LACMVP fossil sites 6306, 6385, 6386; UCMP fossil site PB 98002) (Lander, 2000). The fossil remains from these sites, which lie 0.25 mile south of the Los Angeles River, have been determined to be 7,860 + 80, 8,880 + 60, and 10,500 + 70 years (average: 9,080 + 70 years) (early Holocene) in age (Lander, 2000). Additional land plant remains were recovered at a depth 16 feet below grade at the Metro Red Line North Hollywood station, approximately 1.7 miles north of the Los Angeles River (Lander, 2000).
However, some of the other previously recorded fossil sites yielded the fossilized bones and teeth of extinct late Pleistocene (Ice Age) land mammal species assignable to the Rancholabrean North American Land Mammal Age. LACMVP fossil site 3250, near the intersection of Vermont Avenue and the Hollywood Freeway, yielded fossilized mammoth remains at a depth only 8 feet below grade; LACMVP fossil site 1755, near the intersection of South Hill and West 12th Streets, yielded fossilized horse remains at a depth 43 feet below grade; and fossilized bison remains were uncovered at a depth roughly 35 to 55 feet below grade at a fossil site just west of Union Station in the Metro Red Line tunnel (Jefferson, 1991; Lander, 2000; Miller, 1971). Presumably, the fossil remains from these latter sites are 10,750 to 130,000 years in age (see Jefferson, 1991; Lander, 2000). Additional fossil continental vertebrate and invertebrate remains of presumed late Pleistocene or early Holocene age were encountered at depths at least 30 feet below grade at SBCM fossil sites 09.006.017 to 09.006.021 in the Alameda Corridor approximately 4 miles south of the Project site (Scott, 2001).
The occurrences of these previously recorded fossil site near the Project site suggests there is a potential for additional similar, scientifically important fossil remains being encountered by earth-moving activities at previously unrecorded fossil sites in the alluvium at the Project site where these activities extend to a depth sufficient to encounter remains old enough to be considered fossilized (see McLeod, 2001). Pending further investigation, this potential is considered undetermined. However, within a few feet of the surface, there probably is no more than a low potential for these activities encountering remains old enough to be considered fossilized (see McLeod, 2001). Scott (2001), on the other hand, considered the potential to be low at depths down to at least 30 feet below grade, despite the occurrence of at least one previously recorded fossil site at depth less than 10 feet below grade (see above).
2.2.2.2Artificial Fill.—Artificial fill consists of strata and historic sediment and debris substantially disturbed by human activity. Any fossil remains encountered in the artificial fill would lack any original geologic or geographic context. For this reason, there is no potential for any scientifically important fossil remains or previously unrecorded fossil site being encountered by earth-moving activities in the artificial fill at the Project site.
2.2.3Summary
Presumably, the alluvium spans the Pleistocene/Holocene Epoch boundary. The end of the Pleistocene Epoch is marked by the world-wide extinction of most large land mammal species about 10,750 years ago as a result of overkill arising from intense hunting by prehistoric humans, and/or of severe climatic changes following the end of the last Ice Age and the accompanying alterations of habitat and vegetation that lead to present conditions (Lander, 1988; Lundelius and others, 1987).